JP2010139626A - Optical apparatus, imaging apparatus, and manufacturing method for optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a deviation in relative positional relation between optical members occurring in the course of fixing, and to prevent degradation in optical performance resulting from a change in the ambient temperature. <P>SOLUTION: An optical device includes a first lens 101 and a second lens 102 that are adjacent to each other in a direction of an optical axis. The optical device further includes a holding ring 103 that is formed with a resin material absorbing laser beams and that holds the first lens 101 via an elastic property of the resin material. The second lens 102 is formed with a resin material that allows the laser beams to pass and that is compatible with the resin material forming the holding ring 103, and is fixed to the holding ring 103 by laser welding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical device including a plurality of optical members whose mutual positional relationship is fixed, and an imaging device including the optical device.

  In recent years, with the demand for miniaturization of various devices having an imaging function (hereinafter referred to as “imaging device”) such as a portable phone and a compact camera, an optical member such as a lens mounted on the imaging device or the optical member is installed. There is a tendency that an optical device (optical system) constituted by using a plurality is miniaturized. In recent years, there has been a tendency to increase the number of pixels of an image pickup device in a small image pickup apparatus such as a mobile phone or a compact camera. High optical devices are desired.

  For example, when a throwing-type assembly method is employed, high accuracy can be achieved by narrowing the component tolerance of each optical member constituting the optical device. On the other hand, by reducing the component tolerance of each optical member, the mass productivity of each optical member is lowered, and the yield in mass production of the optical device and the imaging device including the optical device is lowered. In addition, when the throw-in assembly method is used, the accuracy (optical performance) of the optical device depends on the manufacturing accuracy of the component. Therefore, if the component tolerance is widened to improve the mass productivity, the accuracy (optical performance) of the optical device will increase. It will decline.

  A resin product formed by injection molding using a resin material can ensure a relatively high manufacturing accuracy by increasing the precision of the mold technology and improving the precision molding technology. For this reason, conventionally, an optical device in the case of assembling by a throwing type by providing a positioning structure for positioning another optical member on a resin optical member and positioning another optical member by this positioning structure. There was a technology that ensured the accuracy (optical performance).

  In addition, conventionally, for example, by aligning an optical member related to optical performance when assembling an optical device with a reference optical member, so-called alignment is performed, so as to ensure accuracy (optical performance) required for the optical device. There was technology that did. Such alignment is effective when the optical member is made of glass, such as a lens formed by a glass mold method using a glass material.

  In other words, glass optical members formed by a glass molding method using a glass material are difficult to ensure high eccentricity with a single glass optical member. Need. For example, in an optical device such as a lens unit that is designed to be miniaturized by directly joining lenses together, when a resin lens and a glass lens are mixed, a resin lens with high manufacturing accuracy is used. The positional relationship between the resin lens and the glass lens is adjusted by aligning the glass lens.

  Moreover, since it is difficult to ensure manufacturing accuracy of the optical member made of glass alone, it is difficult to provide a highly accurate positioning structure on the optical member made of glass. For this reason, for example, when a resin lens and a glass lens coexist, alignment is performed using an alignment jig. After alignment, the positional relationship between the resin lens and the glass lens is fixed by using, for example, an adhesive that adheres the lens (see, for example, Patent Document 1 below).

  Conventionally, there has been a technique in which a resin lens and a glass lens are fixed using, for example, a UV curable adhesive. The UV curable adhesive is applied by a method such as potting in a state where the positional relationship between the resin lens and the glass lens is fixed by an alignment jig. The alignment jig is removed after the applied adhesive is irradiated with UV light to first cure the UV curable adhesive. The lens after the alignment jig is removed is stored in a place where secondary curing is promoted.

  Conventionally, in an optical pickup, an optical component inserted in the optical path of the optical pickup is held by a base member to which another optical element is attached, formed of a material having a linear expansion coefficient different from that of the base member. There has been a technique of fixing via a member (see, for example, Patent Document 2 below).

JP-A 63-269323 JP-A-7-210892

  However, when the linear expansion coefficients of the optical members fixed to each other by an adhesive are different, such as a resin lens and a glass lens, the conventional technology described above can be expanded or contracted due to a change in environmental temperature. Because of the difference, stress in the compressing or pulling direction acts on the adhesive portion, and the adhesive may be deformed. Then, there is a problem that the optical performance is deteriorated because the positional relationship between the optical members is shifted or the optical members are distorted due to the deformation of the adhesive.

  The deformation of the adhesive becomes more prominent as the environmental temperature changes repeatedly. As the deformation of the adhesive becomes more prominent, the positional relationship between the optical members and the distortion of the optical member more significantly occur. For this reason, the deterioration of the optical performance becomes more remarkable as the environmental temperature changes repeatedly. The problem due to the difference in linear expansion coefficient between members fixed to each other also occurs in the technique of Patent Document 2 described above. Moreover, in the technique of patent document 2 mentioned above, there existed a problem that alignment work could not be performed further.

  In addition, since the UV curable adhesive shrinks after the primary curing until the curing is completed, the alignment jig is removed after the UV curable adhesive is first cured. In the conventional technique, the positional relationship between the resin lens and the glass lens is broken by the adhesive that shrinks in the secondary curing, and the relative positional relationship is shifted. And there existed a problem that the optical performance in an optical apparatus fell because the relative positional relationship between optical members shifted | deviated.

  As a countermeasure, when the alignment jig is removed after the secondary curing is completed, the assembly work cannot be continued for a long time until the alignment jig is removed. There arises a problem that the yield in mass production of an optical apparatus and an imaging apparatus having an optical system is lowered. Further, in this case, it is necessary to secure a place for storing the lens to which the alignment jig is attached for a long time until the alignment jig is removed, which causes an increase in production cost. .

  In order to eliminate the above-described problems caused by the prior art, the present invention can prevent a relative positional relationship between optical members in a fixing process and a decrease in optical performance due to a change in environmental temperature. It is an object to obtain an optical device, an imaging device, and a method for manufacturing the optical device.

  In order to solve the above-described problems and achieve the object, an optical device according to the present invention is an optical device including a first optical member and a second optical member that are arranged adjacent to each other in the optical axis direction. And a holding member that is formed of a resin material that absorbs laser light and holds the first optical member by the elastic force of the resin material, and the second optical member transmits the laser light and holds the holding member. It is formed of a resin material having compatibility with the material forming the member, and is fixed to the holding member by laser welding.

  According to the present invention, the holding member that holds the first optical member and the second optical member can be fixed in a short time by laser welding. By fixing by laser welding in a short time, relative to the first optical member and the second optical member at the time of fixing, for example, when fixing using an adhesive with volume shrinkage during curing. Can be prevented from shifting.

  According to the present invention, the holding member is elastically deformed according to a shape change such as expansion or contraction of the first optical member due to a change in environmental temperature, so that the position of the first optical member with respect to the holding member is changed. Can be stabilized.

  Furthermore, according to the present invention, when the environmental temperature changes after the holding member and the second optical member are fixed, the holding member and the second optical member formed by the resin material are deformed to hold the holding member. Deviation in the positional relationship between the member and the second optical member can be suppressed.

  The optical device according to the present invention is characterized in that, in the above invention, the first optical member is made of glass. According to this invention, even when the first optical member and the second optical member are formed of different materials, the holding member and the second optical member that hold the first optical member formed of glass are used. By fixing the member by laser welding, the positional relationship between the first optical member and the second optical member due to a change in the environmental temperature after fixing can be suppressed.

  In the optical device according to the present invention, in the above invention, the holding member is formed of a material obtained by mixing a resin material serving as a base with a material that absorbs laser light, and the second optical member includes It is formed by the material which mixed the resin material which is the same kind as the resin material used as a base, and the material which permeate | transmits the said laser beam.

  According to the present invention, since the holding member and the second optical member are formed using the same type of resin material as a base, even when each optical member expands or contracts due to a change in environmental temperature, the volume changes. The positional relationship between optical members due to the difference in linear expansion coefficient of each member and the occurrence of distortion in each member can be prevented.

  The imaging device according to the present invention is formed of a resin material that absorbs laser light, and holds a first optical member by the elastic force of the resin material, and the first optical member in the optical axis direction. A second optical element disposed adjacent to each other, formed of a resin material that transmits the laser light and is compatible with a material that forms the holding member, and is fixed to the holding member by laser welding. And a photoelectric conversion element for imaging that converts external light received through the first optical member and the second optical member into an electrical signal.

  According to the present invention, the holding member that holds the first optical member and the second optical member can be fixed in a short time by laser welding. Positioning between the first optical member and the second optical member at the time of fixing, for example, in the case of fixing using an adhesive with volume shrinkage during curing by fixing by laser welding in a short time Can be prevented, and stable imaging performance can be ensured.

  According to the present invention, the holding member is elastically deformed according to a shape change such as expansion or contraction of the first optical member due to a change in environmental temperature, so that the position of the first optical member with respect to the holding member is changed. It is possible to stabilize and ensure stable imaging performance.

  Furthermore, according to the present invention, when the environmental temperature changes after the holding member and the second optical member are fixed, the holding member and the second optical member formed by the resin material are deformed to hold the holding member. A shift in the positional relationship between the member and the second optical member can be suppressed, and stable imaging performance can be ensured.

  The method for manufacturing an optical device according to the present invention includes a first optical member and a second optical member that are formed using materials having different linear expansion coefficients and are arranged adjacent to each other in the optical axis direction. A method of manufacturing an optical device in which the second optical member is formed of a resin material that transmits laser light, and is compatible with a material that absorbs the laser light and forms the second optical member. A step of holding the first optical member by a ring-shaped holding member formed of a resin material having the first optical member held by the holding member with respect to the optical axis of the second optical member; The step of aligning the optical axis of the optical member, and the holding member and the second optical member in a state where the optical axis of the first optical member is aligned with the optical axis of the second optical member. A contact step; A step of irradiating the holding member in contact with the second optical member with the laser light via the second optical member, and a step of stopping the irradiation of the laser light. To do.

  According to the present invention, the positional relationship between a plurality of optical members formed using materials having different linear expansion coefficients can be fixed easily and reliably in a short time. In addition, according to the present invention, after fixing the positional relationship between the plurality of optical members, even when there is a change in the shape of the optical member such as expansion or contraction due to a change in environmental temperature, Deviations in the positional relationship among the plurality of optical members can be suppressed, and stable imaging performance can be ensured.

  According to the optical device and the imaging device according to the present invention, it is possible to prevent the relative positional relationship between the optical members during the fixing process and the deterioration of the optical performance due to the change in the environmental temperature. Play.

  Exemplary embodiments of an optical apparatus and an imaging apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings. In this embodiment, an example of application to a lens apparatus is shown as an optical apparatus according to the present invention.

  First, a schematic configuration of a lens apparatus according to an embodiment of the present invention will be described. The lens device according to the embodiment of the present invention includes a plurality of lenses as optical members. Each of the plurality of lenses is provided inside a lens barrel having a substantially cylindrical shape.

  Some or all of the plurality of lenses are provided to be movable relative to the lens barrel along the optical axis direction. Since the shape of the lens barrel and the moving mechanism of each lens in the lens barrel can be easily realized by using a known technique, description thereof will be omitted. Some lenses of the plurality of lenses constitute a unitized lens group. The lens group may be movable relative to the lens barrel along the optical axis direction, or the relative position with respect to the lens barrel may be fixed.

  The lens device is attached to a mount or the like included in the imaging device main body (not shown). An imaging photoelectric conversion element, that is, an imaging element (not shown) is disposed in the imaging apparatus main body. The image sensor photoelectrically converts external light incident through the lens device and outputs an electrical signal corresponding to the amount of incident light. Specifically, the imaging device can be realized by a solid-state imaging device such as a CCD image sensor (Charge Coupled Device Image Sensor) or a CMOS image sensor (Complementary Metal Oxide Semiconductor Image Sensor).

  Next, a lens group included in the lens device according to the embodiment of the present invention will be described. 1 and 2 are explanatory views showing lens groups provided in the lens apparatus according to the embodiment of the present invention. In FIG. 1, the lens group with which the lens apparatus of embodiment concerning this invention is provided is shown in the state seen from the direction which cross | intersects an optical axis. FIG. 2 shows a cross section (AA cross section in FIG. 1) in which the lens group included in the lens apparatus according to the embodiment of the present invention is cut along a plane passing through the optical axis and parallel to the optical axis.

  1 and 2, the lens group 100 included in the lens device according to the embodiment of the present invention includes a first lens 101, a second lens 102, and a third lens 201. The first lens 101, the second lens 102, and the third lens 201 are provided in a lens barrel (not shown) with the optical axes of the lenses 101, 102, and 201 aligned. In this embodiment, aligning the optical axes of the first lens 101, the second lens 102, and the third lens 201 will be described as “alignment”.

  The first lens 101 is formed by a glass mold method using a glass material. The first lens 101 may be formed using a glass material, or may be formed using a material other than a glass material such as a resin material. In this embodiment, the first optical member can be realized by the first lens 101. The first lens 101 is held by a holding ring 103.

  The holding ring 103 has a substantially ring shape with the optical axis C as the center. The inner circumferential surface of the holding ring 103 has a small-diameter portion 104 in which the dimension in the radial direction of the circle centered on the optical axis C is smaller than the radius of the first lens 101, and the dimension in the radial direction of the circle centered on the optical axis. The large diameter part 105 larger than the radius of the 1st lens 101 has the unevenness | corrugation which appears alternately along the circumferential direction. The small diameter portion 104 and the large diameter portion 105 are connected via a connecting portion 106.

  The holding ring 103 has an annular shape by connecting the small diameter portion 104, the large diameter portion 105, and the connecting portion 106 in order. The small-diameter portion 104, the large-diameter portion 105, and the connecting portion 106 are provided at equal intervals on a concentric circle with the optical axis C as the center. In this embodiment, the small-diameter portion 104, the large-diameter portion 105, and the connecting portion 106 are provided at three locations, respectively.

  The small diameter portion 104 of the presser ring 103 is provided so as to be displaceable in a direction away from the optical axis C in a plane orthogonal to the optical axis C. The connecting portion 106 is displaced with the displacement of the small diameter portion 104. The small-diameter portion 104 and the connecting portion 106 are displaced in a direction so as to be positioned between the large-diameter portions 105 on the same circumference around the optical axis C. As a result, the holding ring 103 can be deformed in the direction in which the inner diameter is expanded by displacing the small diameter portion 104 and the connecting portion 106.

  The first lens 101 is positioned on the inner peripheral portion of the holding ring 103 that has been deformed so as to widen the inner diameter. The holding ring 103 holds the first lens 101 by bringing the small diameter portion 104 into contact with the outer peripheral edge of the first lens 101 and applying an urging force from the small diameter portion 104 toward the optical axis C to the first lens 101. ing. In this embodiment, the holding member can be realized by the pressing ring 103. In the presser ring 103, the urging force from the small diameter portion 104 toward the optical axis is caused by the elastic force of the material forming the presser ring 103, and the expanded small diameter portion 104 attempts to return to the original position. Due to

  The outer diameter dimension of the first lens 101 is larger than the diameter dimension of a circle centered on the optical axis C formed by the small diameter portion 104. Thereby, in the holding ring 103 in a state where the first lens 101 is held, the urging force to return to the original shape, that is, the inner diameter dimension is contracted by the elasticity of the resin material forming the holding ring 103. The urging force of acts.

  As described above, the first lens 101 having an outer diameter larger than the inner diameter of the presser ring 103 can be positioned on the inner peripheral side of the presser ring 103, and the first lens 101 can be held by the elastic force of the presser ring 103. By holding the first lens 101 by the elastic force of the holding ring 103, the positional relationship between the holding ring 103 and the first lens 101 can be fixed without using an adhesive or the like.

  The presser ring 103 includes a protrusion 107 that protrudes from the inner peripheral surface of the presser ring 103 toward the optical axis direction. A plurality of projections 107 (three in this embodiment) are provided, and each is provided on the small diameter portion 104. Thus, the plurality of protrusions 107 are provided at equal intervals on concentric circles with the optical axis C as the center. The protrusion 107 is provided so as to come into contact with the first lens 101 from one end side in the optical axis direction in a state where the first lens 101 is held by the pressing ring 103.

  The holding ring 103 abuts the plurality of protrusions 107 on one surface side of the first lens 101 and biases the first lens 101 toward one side (lens holder side) in the optical axis direction with respect to the first lens 101. The first lens 101 is held by applying an urging force. It is preferable that the small-diameter portion 104 and the protrusion 107 abut on the first lens 101 at three locations or more than three locations on the same circumference centered on the optical axis C.

  The locations where the small diameter portion 104 and the protrusion 107 abut on the first lens 101 are preferably 3 or multiples of 3. Thereby, an equal urging force can be applied to the entire first lens 101, and the first lens 101 can be stably held.

  The retainer ring 103 is formed by an injection molding method using a resin material. By forming by the injection molding method using a resin material, the pressing ring 103 can be formed with high accuracy. The resin material forming the holding ring 103 has a property of absorbing laser light.

  Specifically, the resin material forming the presser ring 103 can be configured, for example, by mixing or dispersing a material that absorbs laser light in a resin material serving as a base. In this embodiment, for example, a black polycarbonate (PC) resin material can be used.

  Laser (LASER: Light Amplification Stimulated Emission of Radiation) light is coherent light obtained by amplifying light (electromagnetic wave), and for example, a wavelength in the near infrared region can be used. Specifically, for example, a YAG laser can be used. More specifically, it is preferable to use a laser beam with a wavelength of 800 to 1100 nm using, for example, a YAG laser, a YVO4 laser, a semiconductor laser, or the like.

  YAG in a YAG laser is derived from the initials of yttrium, aluminum, and garnet. YVO4 in the YVO4 laser is an abbreviation for yttrium vanadate (YVO4) and represents a kind of laser medium of a solid-state laser oscillator. The laser light is not limited to the wavelength in the near infrared region, but may be a wavelength shorter than visible light such as ultraviolet rays or X-rays, or a wavelength longer than visible light such as infrared rays.

  The linear expansion coefficient of the resin material forming the pressing ring 103 is different from the linear expansion coefficient of the glass material forming the first lens 101. As a result, when a change in environmental temperature that causes a volume change in the first lens 101 and the holding ring 103 occurs, such as expansion or contraction, the first lens 101 and the holding ring 103 have different volumes. Showing change.

  The second lens 102 is disposed adjacent to the first lens 101 along the optical axis direction. The second lens 102 is formed by an injection molding method using a resin material. By forming by an injection molding method using a resin material, the second lens 102 can be formed with high accuracy.

  The resin material forming the second lens 102 is compatible with the resin material forming the presser ring 103. Specifically, the resin material forming the second lens 102 can be realized by, for example, the same type of resin material as the base resin material in the material forming the pressing ring 103. In this embodiment, for example, a resin material mainly composed of PC can be used. The resin material forming the second lens 102 has a property of transmitting laser light.

  Specifically, the resin material forming the second lens 102 can be configured, for example, by mixing or dispersing a material that transmits laser light into a resin material serving as a base. More specifically, for example, the second lens 102 is formed by mixing or dispersing a material that transmits laser light in the same type of resin material as the base material in the material forming the holding ring 103. A resin material can be configured. In this embodiment, for example, a transparent PC resin material can be used. In this embodiment, the second optical member can be realized by the second lens 102.

  The second lens 102 is joined to the holding ring 103 by laser welding. In FIG. 1 and FIG. 2, a joint portion between the second lens 102 and the pressing ring 103 by laser welding is indicated by a symbol W. In laser welding, a member to be joined formed of a thermoplastic resin material is heated using a laser beam until the melting point of the resin material is exceeded, and pressure is applied in a state where the temperature has been raised. This technique is known as a technique for joining members at the molecular level.

  In laser welding, basically, a joining target member (hereinafter referred to as “laser light absorbing member” as appropriate) formed of a thermoplastic resin material having a property of absorbing laser light, and a property of transmitting laser light. A laser beam is irradiated from the laser beam transmitting member side to an interface where a joining target member (hereinafter, referred to as “laser beam transmitting member” as appropriate) formed of a thermoplastic resin material having a contact is made.

  In addition to laser welding, techniques for joining members to be joined formed of thermoplastic resin materials at the molecular level include impulse welding, hot plate welding, non-contact hot plate welding, ultrasonic welding, high frequency welding, vibration welding, Although there is infrared welding or the like, the irradiation range of the laser beam can be made extremely small. Therefore, even when the member to be joined is small, it is possible to reliably join by using laser welding. In addition, since laser welding can be joined without using vibration, it is possible to prevent the occurrence of adverse effects such as damage to the joining target member due to vibration during joining.

  The resin material used for laser welding can be configured by including various color materials in a predetermined material serving as a base. Specifically, as the thermoplastic resin material having the property of absorbing laser light, for example, a resin material containing a coloring material that is efficient in absorbing laser light in the wavelength range to be used and converting it to heat is used. be able to. Specifically, as the thermoplastic resin material having a property of transmitting laser light, for example, a resin material containing a dye-based coloring material that transmits almost the laser light in the wavelength range to be used can be used. .

  Laser welding causes irradiated laser light to reach the laser light absorbing member without melting the surface of the laser light transmitting member, and raises the temperature of the laser light absorbing member higher than the melting point of the laser light absorbing member. Then, the heat of the laser light absorbing member is conducted to the laser light transmitting member to dissolve the laser light transmitting member. The laser light absorbing member and the laser light transmitting member are mixed with each other in the melted portion. When the irradiation of the laser beam is stopped, the temperature of the melted resin material falls below the melting point, and the welding is completed.

  By joining the members to be joined using laser welding, the members to be joined can be joined without using an adhesive. Thereby, the adverse effect on the environment caused by using the adhesive can be suppressed. Further, since no adhesive is required, the weight can be reduced as compared with the case where an adhesive is used.

  The third lens 201 is formed by an injection molding method using a resin material. By forming by the injection molding method using a resin material, the third lens 201 can be formed with high accuracy. The third lens 201 includes a stepped portion 202 for positioning. The positioning step 202 determines the positional relationship between the third lens 201 and the second lens 102.

  The second lens 102 includes a protrusion 107 protruding toward the third lens 201, and the position of the third lens 201 with respect to the second lens 102 is determined by fitting the stepped portion 202 to the protrusion 107. In a state where the stepped portion 202 is fitted into the protrusion 107, a space is formed in a part between the second lens 102 and the third lens 201 in the optical axis direction. This space has a ring shape centered on the optical axis C.

  An adhesive 203 is provided in this space, and the positional relationship between the second lens 102 and the third lens 201 is fixed by the adhesive 203. The adhesive 203 is preferably provided in a part of a space having a ring shape. Accordingly, the weight of the lens group 100 can be reduced, and the positional relationship between the second lens 102 and the third lens 201 can be prevented from being shifted due to the volume change accompanying the curing of the adhesive 203. By using, for example, a UV curable adhesive as the adhesive 203, it is possible to ensure high workability for assembling the lens group 100.

  Next, a method for joining the pressing ring 103 and the second lens 102 will be described. FIG. 3 is an explanatory view showing a method of joining the presser ring 103 and the second lens 102. In FIG. 3, when the pressing ring 103 and the second lens 102 are joined, first, the position of the pressing ring 103 with respect to the second lens 102 is determined. Specifically, the position of the pressing ring 103 with respect to the second lens 102 can be set, for example, to a position where the optical axis of the first lens 101 held by the pressing ring 103 is aligned with the optical axis of the second lens 102.

  The position of the optical axis of the first lens 101 relative to the optical axis of the second lens 102, that is, the position of the pressing ring 103 with respect to the second lens 102 intersects the optical axis of the pressing ring 103 that holds the first lens 101. Adjustment is performed by moving the lens relative to the second lens 102 within the plane (see arrow S).

  When the positional relationship between the pressing ring 103 and the second lens 102 is a positional relationship in which the optical axis of the first lens 101 is aligned with the optical axis of the second lens 102, the pressing ring 103 and the second lens 102 Is fixed using a predetermined jig. This jig is only required to be able to temporarily fix the positional relationship between the holding ring 103 and the second lens 102, and is preferably one that can be removed after joining by laser welding.

  Next, laser light is irradiated from the second lens 102 side to the holding ring 103 and the second lens 102 fixed by the jig. Laser light irradiation is performed using a predetermined laser light irradiation device 301. The laser light irradiation device 301 includes a laser light source 302 and a lens 303 that condenses the laser light emitted from the laser light source 302. Since the laser beam irradiation apparatus 301 can be easily realized by using various known techniques, description thereof is omitted.

  The irradiated laser light passes through the second lens 102 and reaches the holding ring 103. Since the resin material forming the presser ring 103 has a property of absorbing laser light, the laser light that has reached the presser ring 103 is absorbed by the presser ring 103 and converted into thermal energy in the presser ring 103. The thermal energy converted from the light energy in the presser ring 103 raises the temperature of the presser ring 103. In the presser ring 103, only the resin material at a location where the temperature has been raised to a temperature higher than the melting point melts to form a molten pool 304.

  Since the second lens 102 is in contact with the holding ring 103, the heat energy generated in the holding ring 103 and forming the molten pool 304 is conducted to the second lens 102, and the temperature of the second lens 102 is raised. Let In the second lens 102, only the resin material at a location where the temperature has been raised to a temperature higher than the melting point is melted to form a molten pool 305. The resin material forming the molten pool 304 in the holding ring 103 and the resin material forming the molten pool 305 in the second lens 102 are mixed with each other to form one molten pool 306. One molten pool 306 includes a resin material that forms the pressing ring 103 and a resin material that forms the second lens 102.

  Since the holding ring 103 and the second lens 102 are formed using compatible resin materials, one molten pool formed by the molten pool 304 in the holding ring 103 and the molten pool 305 in the second lens 102. In 306, the resin material forming the presser ring 103 and the resin material forming the second lens 102 are uniformly mixed without unevenness.

  After one melt pool 306 is formed by the press ring 103 and the second lens 102, when the laser beam irradiation is stopped, the temperature of the resin material in the one melt pool 306 is lowered and solidified. Since one molten pool 306 is a mixture of the resin material forming the presser ring 103 and the resin material forming the second lens 102, the temperature of the resin material in one molten pool 306 decreases and solidifies. As a result, the pressing ring 103 and the second lens 102 are joined via the resin material that forms one molten pool 306.

  Since the laser beam can irradiate an accurate position within a small irradiation range, a molten pool can be formed and bonded only at a position where the press ring 103 and the second lens 102 are to be bonded. Thereby, the holding ring 103 and the second lens 102 can be joined without impairing the aesthetic appearance of the joined portion.

  The location where the laser beam is irradiated may be one location or a plurality of locations. When irradiating laser light to a plurality of locations, it is preferable to irradiate the laser light on the same circumference centered on the optical axis C. Moreover, when irradiating a laser beam to several places, it is preferable to irradiate a laser beam at equal intervals on the same periphery centering on the optical axis C. FIG.

  The portion irradiated with the laser light is preferably the large diameter portion 105. Accordingly, the pressing ring 103 and the lens holder can be fixed by laser welding without affecting the deformation of the pressing ring 103 accompanying the change in the outer diameter of the first lens 101, that is, the displacement of the small diameter portion 104. .

  The number of places to which laser light is irradiated is the same as the number of contact portions between the small diameter portion 104 and the first lens 101, and is on the same circumference as the contact portion between the small diameter portion 104 and the first lens 101. It is preferable to set it as an intermediate position between the contact points. When irradiating a plurality of places with laser light, it is preferable to irradiate each irradiation place simultaneously. The irradiation method in the case of irradiating a plurality of locations with laser light is not limited to irradiating each irradiation location at a completely coincident timing, and it is only necessary to irradiate all the irradiation locations within a short time that can be regarded as almost simultaneous.

  As described above, the lens device according to the embodiment as an example of the optical device according to the present invention includes the first lens 101 and the second lens as examples of the first optical member arranged adjacent to each other in the optical axis direction. As an example of a holding device that includes a second lens 102 as an example of the optical member, and is formed of a resin material that absorbs laser light, and holds the first lens 101 by the elastic force of the resin material. The second lens 102 is formed of a resin material that transmits laser light and is compatible with the material forming the presser ring 103, and is fixed to the presser ring 103 by laser welding. It is characterized by.

  According to the above configuration, the holding ring 103 that holds the first lens 101 and the second lens 102 can be fixed in a short time by laser welding. Then, by fixing in a short time by laser welding, the first lens 101 and the second lens 102 are fixed relative to each other at the time of fixing, for example, when fixing using an adhesive 203 with volume shrinkage in the middle of curing. Can be prevented from shifting.

Specifically, for example, the first lens 101 is formed using glass (K-PFK85) having a linear expansion coefficient of 129 × 10 ⁻⁷ , and PC resin (AD5503) having a linear expansion coefficient of 700 × 10 ^−7. When the second lens 102 is formed using the second lens 102, the second lens 102, which is a resin lens, expands more than the first lens 101, which is a glass lens, when the environmental temperature increases. In this case, when the environmental temperature is lowered, the first lens 101 that is a glass lens contracts more than the second lens 102 that is a resin lens.

  FIG. 4 is an explanatory view showing a conventional lens group. FIG. 4 shows a state in which the conventional lens group is viewed from a direction intersecting the optical axis, and a cross section cut along a plane passing through the optical axis and parallel to the optical axis. In the conventional lens group, the same or similar parts as those of the lens group 100 described above are denoted by the same reference numerals. In FIG. 4, in the conventional lens group, the first lens 101 and the second lens 102 are fixed by a conventional fixing method using an adhesive 401.

  As described above, since the linear expansion coefficients of the first lens 101 and the second lens 102 are different, a difference occurs in the degree of expansion / contraction between the first lens 101 and the second lens 102 due to a change in environmental temperature. When a difference occurs in the degree of expansion and contraction, stress in the compression or tension direction acts on the adhesive 401 portion, and the adhesive 401 may be deformed.

  When the adhesive is deformed, the positional relationship between the first lens 101 and the second lens 102 may be shifted, or the first lens 101 or the second lens 102 may be distorted. As described above, in the conventional fixing method using the adhesive 401, the optical performance may be deteriorated due to a change in the environmental temperature. The deformation of the adhesive 401 becomes more prominent as the environmental temperature changes repeatedly. As the deformation of the adhesive 401 becomes more prominent, the positional relationship between the first lens 101 and the second lens 102 and the distortion of the first lens 101 or the second lens 102 become more prominent. For this reason, the deterioration of the optical performance becomes more remarkable as the environmental temperature changes repeatedly.

  In response to such a problem in the conventional lens group, according to the lens device of this embodiment, the presser ring 103 is moved in accordance with a shape change such as expansion or contraction of the first lens 101 caused by a change in environmental temperature. Elastically deforms. That is, since the holding ring 103 can be deformed according to the shape change of the first lens 101, the difference in the amount of change when the shape of the first lens 101 changes more greatly than the second lens 102 due to the change of the environmental temperature. Can be absorbed by the deformation of the holding ring 103. As a result, the position of the first lens 101 with respect to the holding ring 103 can be stabilized, and a shift in the relative positional relationship between the first lens 101 and the second lens 102 can be prevented.

  Further, according to the lens apparatus of this embodiment, the difference in the amount of change when the second lens 102 changes in shape more greatly than the first lens 101 due to the change in the environmental temperature is absorbed by the deformation of the pressing ring 103. The deformation of the second lens 102 can be suppressed. As a result, internal stress generated in the third lens 201 positioned with respect to the second lens 102 can be relaxed. As a result, the position of the first lens 101 with respect to the positioning portion in the second lens 102 can always be stabilized.

  Furthermore, according to the lens device of this embodiment, when the environmental temperature changes after the holding ring 103 and the second lens 102 are fixed, the holding ring 103 and the second lens 102 formed of a resin material are Deform. Accordingly, the positional relationship between the holding ring 103 and the second lens 102 can be suppressed, and the relative positional relationship between the first lens 101 and the second lens 102 can be prevented from shifting.

  Moreover, according to the imaging device provided with the lens device of this embodiment, the pressing ring 103 holding the first lens 101 and the second lens 102 can be fixed in a short time by laser welding. Accordingly, it is possible to prevent the positional relationship between the first lens 101 and the second lens 102 from being shifted during fixing, for example, when fixing using the adhesive 401 having volume shrinkage in the middle of curing.

  Further, according to the imaging apparatus including the lens device of this embodiment, the pressing ring 103 is elastically deformed according to a shape change such as expansion or contraction of the first lens 101 due to a change in the environmental temperature. The position of the first lens 101 with respect to the ring 103 can be stabilized. Furthermore, according to the imaging device including the lens device of this embodiment, when the environmental temperature changes after the pressing ring 103 and the second lens 102 are fixed, the pressing ring 103 formed of a resin material and the second Deformation of the two lenses 102 can suppress a shift in the positional relationship between the press ring 103 and the second lens 102.

  As a result, the lens device is caused by the relative positional relationship between the first lens 101 and the second lens 102 in the fixing process, the positional relationship between the members due to the environmental temperature change, and the occurrence of distortion in each member. The optical performance can be prevented from deteriorating. Then, by preventing the optical performance of the lens device from being deteriorated, it is possible to prevent deterioration of the image quality of the captured image.

  In the above-described embodiment, an example of application to an optical device such as a lens device has been described. However, the member coupling mechanism according to the present invention is not limited to application to an optical device. The member connecting mechanism according to the present invention can be applied to various apparatuses including a plurality of members fixed using laser welding.

  As described above, the optical device and the imaging device according to the present invention are useful for an optical device including a plurality of optical members whose mutual positional relationship is fixed, and an imaging device including the optical device. It is suitable for an optical device including a plurality of optical members that are difficult to fix and an imaging device including the optical device.

It is explanatory drawing (the 1) which shows the lens group with which the lens apparatus of embodiment concerning this invention is provided. It is explanatory drawing (the 2) which shows the lens group with which the lens apparatus of embodiment concerning this invention is provided. It is explanatory drawing which shows the joining method of a holding ring and a 2nd lens. It is explanatory drawing which shows the conventional lens group.

Explanation of symbols

100 lens group 101 first lens 102 second lens 103 holding ring

Claims (5)

An optical device including a first optical member and a second optical member arranged adjacent to each other in the optical axis direction,
A holding member that is formed of a resin material that absorbs laser light and holds the first optical member by the elastic force of the resin material,
The second optical member is formed of a resin material that transmits the laser light and has compatibility with a material forming the holding member, and is fixed to the holding member by laser welding. Optical device characterized.   The optical device according to claim 1, wherein the first optical member is made of glass. The holding member is formed of a material obtained by mixing a material that absorbs laser light into a resin material serving as a base,
The said 2nd optical member is formed with the material which mixed the material which permeate | transmits the said laser beam in the resin material of the same kind as the resin material used as the said base, The Claim 1 or 2 characterized by the above-mentioned. The optical device described. A holding member that is formed of a resin material that absorbs laser light and holds the first optical member by the elastic force of the resin material;
It is disposed adjacent to the first optical member in the optical axis direction, and is formed of a resin material that transmits the laser light and is compatible with a material that forms the holding member. A second optical member fixed by laser welding;
A photoelectric conversion element for imaging that converts external light received through the first optical member and the second optical member into an electrical signal;
An imaging apparatus comprising: A first optical member and a second optical member, which are formed using materials having different linear expansion coefficients from each other and are arranged adjacent to each other in the optical axis direction, transmit laser light through the second optical member. A method of manufacturing an optical device formed of a resin material,
A step of holding the first optical member by a holding member having a ring shape formed of a resin material that absorbs the laser light and is compatible with a material forming the second optical member;
Aligning the optical axis of the first optical member held by the holding member with respect to the optical axis of the second optical member;
Contacting the holding member and the second optical member with the optical axis of the first optical member aligned with the optical axis of the second optical member;
Irradiating the holding member in contact with the second optical member with the laser light through the second optical member;
Stopping the laser light irradiation;
A method for manufacturing an optical device, comprising:

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